Pressure sensor having a helmholtz resonator

ABSTRACT

This disclosure provides example methods, devices, and systems for a sensor having a Helmholtz resonator. In one embodiment, a system may comprise a sensing element; a header coupled to the sensing element; a housing coupled to the header; an adaptor coupled to the housing; a screen disposed in an opening of the housing, wherein a first cavity is disposed between the screen and the sensing element and a second cavity is disposed between the adaptor and the sensing element, and the screen in combination with the first cavity and the second cavity form a Helmholtz resonator.

FIELD OF THE INVENTION

This invention relates to sensors and more particularly to a pressuresensor having a Helmholtz resonator.

BACKGROUND OF THE INVENTION

Pressure sensors are widely employed in many environments in order tomonitor pressure. For instance, pressure sensors may operate in harshenvironments such as monitoring pressure in internal combustion enginesor aircraft engines, as well as in other environments subjected to highpressures or high temperatures. In a typical pressure sensor, a pressuresensing element may be packaged in a round, glass-metal seal header.This header may be welded onto a screw housing. The screw housing may bemounted to a mating surface such as associated with a port of an engine,forming a seal between the screw housing and the mating surface. Sincethe seal is formed by the screw housing and the mating surface, anystress caused by the seal may not be transferred to the header. Thisconfiguration may work well for many applications but may not work wellfor applications requiring a seal associated with the front of a sensor.The use a sensor having a front seal is common in combustionmeasurements requiring a reduced volume. For a typical sensor having afront seal, the seal may be formed, for instance, directly between theheader surface and the surface of the engine or on an adaptor welded tothe housing, which may be in close proximity to the header. However, thefront seal may place undue stress on the header, which may cause thisstress to be transferred to the sensing element.

FIG. 1 shows a prior art sensor 100 having a front seal. A glass sealheader 101 is coupled to a sensing element 102. For many applications,this may be done using a piezoresistive leadless sensor. These sensorsare made of silicon and have been widely employed. In one example ofsuch sensor, reference is made to U.S. Pat. No. 5,955,771, entitled“SENSORS FOR USE IN HIGH-VIBRATIONAL APPLICATIONS AND METHODS FORFABRICATING THE SAME” issued on Sep. 21, 1999 to A. D. Kurtz, et al. andassigned to Kulite Semiconductor Products Inc, the assignee herein. Inanother example, reference is made to U.S. Pat. No. 5,973,590, entitled“ULTRA THIN SURFACE MOUNT WAFER SENSOR STRUCTURES AND METHODS FORFABRICATING THE SAME” issued on Oct. 26, 1999 to A. D. Kurtz, et al. andassigned to Kulite Semiconductor Products Inc, the assignee herein. Eachof these patents is incorporated herein in their entirety. Thisconfiguration allows use of the front seal sensor 100 in hightemperature, high vibration environments. The glass seal header 101 iswelded to a screw housing 103, which allows the front seal sensor 100 tobe threaded into a port of, for instance, an engine. The glass sealheader 101 encloses the sensing element 102. Further, a first adaptor104 is welded or press fit to the screw housing 103. A second adapter105 is welded to the first adaptor 104. The second adaptor 105 has afront surface 106, which allows for sealing the front seal sensor 100against a mating surface during installation. Since this is ametal-to-metal seal, a large amount of stress is generated in formingthe seal. This stress is transferred to the sensing element 102, whichmay result in reduced accuracy of measurements made by the sensingelement 102. Accordingly, there is a need for techniques to allow forreducing an amount of stress transferred to a sensing element of asensor having a front seal. Further, there is a need for techniques toimprove pressure sensors having a Helmholtz resonator. In addition,other desirable features and characteristics of the present disclosurewill become apparent from the subsequent detailed description andclaims, taken in conjunction with the accompanying figures and theforegoing technical field and background.

SUMMARY OF THE INVENTION

Briefly described, embodiments of the present disclosure relate to asensor having a front seal. Furthermore, embodiments of the presentdisclosure relate to a sensor having a Helmholtz resonator. In oneexample embodiment, a system may include a sensing element, a header, ahousing and an adaptor. The header may be coupled to the sensing elementand the housing may be coupled to the header. Also, the adaptor may becoupled to the housing. A first gap may separate the adapter and thesensing element. Also, a second gap may separate the adapter and theheader. A stress applied to the adapter may be transferred to thehousing. The first gap may be used to isolate the sensing element fromthe stress. Further, the second gap may be used to isolate the headerfrom the stress.

In another example embodiment, a system may include a sensing element, aheader, a housing, an adaptor and a screen. The header may be coupled tothe sensing element and the housing may be coupled to the header. Also,the adaptor may be coupled to the housing. Further, the screen may bedisposed in an opening of the housing. A first cavity may be disposedbetween the screen and the sensing element. A second cavity may bedisposed between the adaptor and the sensing element. The screen incombination with the first cavity and the second cavity may form aHelmholtz resonator.

In another example embodiment, a system may include a sensing element, aheader, a housing, an adaptor and a screen. The header may be coupled tothe sensing element and the housing may be coupled to the header. Also,the adaptor may be coupled to the housing. Further, the screen may bedisposed in an opening of the housing. A first cavity may be disposedbetween the screen and the sensing element. A second cavity may bedisposed between the adaptor and the sensing element. Further, a thirdcavity may be disposed between the adaptor and the heading. The screenin combination with the first cavity, the second cavity and the thirdcavity may form a Helmholtz resonator.

BRIEF DESCRIPTION OF THE FIGURES

The present disclosure is illustrated by way of examples, embodimentsand the like and is not limited by the accompanying figures, in whichlike reference numbers indicate similar elements. Elements in thefigures are illustrated for simplicity and clarity and have notnecessarily been drawn to scale. The figures along with the detaileddescription are incorporated and form part of the specification andserve to further illustrate examples, embodiments and the like, andexplain various principles and advantages, in accordance with thepresent disclosure, where:

FIG. 1 is a prior art sensor having a front seal.

FIG. 2 is a partial longitudinal cross-sectional view of one embodimentof a sensor having a front seal with various aspects set forth herein.

FIG. 3 is a top view of another embodiment of a sensor having a frontseal with various aspects set forth herein.

FIG. 4 is a partial longitudinal cross-sectional view of anotherembodiment of a sensor having a front seal and a Helmholtz resonatorwith various aspects set forth herein.

DETAILED DESCRIPTION OF THE INVENTION

The following detailed description is merely illustrative in nature andis not intended to limit the present disclosure, or the application anduses of the present disclosure. Furthermore, there is no intention to bebound by any expressed or implied theory presented in the precedingfield of use, background, or summary of the disclosure or the followingdetailed description. The present disclosure provides various examples,embodiments and the like, which may be described herein in terms offunctional or logical block elements. Various techniques describedherein may be used for a sensor having a front seal and a sensor havinga Helmholtz resonator. The various aspects described herein arepresented as methods, devices (or apparatus), and systems that mayinclude a number of components, elements, members, modules, nodes,peripherals, or the like. Further, these methods, devices, and systemsmay include or not include additional components, elements, members,modules, nodes, peripherals, or the like.

Throughout the specification and the claims, the following terms take atleast the meanings explicitly associated herein, unless the contextclearly dictates otherwise. The terms “connect,” “connecting,” and“connected” mean that one function, feature, structure, orcharacteristic is directly joined to or in communication with anotherfunction, feature, structure, or characteristic. The terms “couple,”“coupling,” and “coupled” mean that one function, feature, structure, orcharacteristic is directly or indirectly joined to or in communicationwith another function, feature, structure, or characteristic. Relationalterms such as “first” and “second,” and the like may be used solely todistinguish one entity or action from another entity or action withoutnecessarily requiring or implying any actual such relationship or orderbetween such entities or actions. The term “or” is intended to mean aninclusive or. Further, the terms “a,” “an,” and “the” are intended tomean one or more unless specified otherwise or clear from the context tobe directed to a singular form. The term “include” and its various formsare intended to mean including but not limited to. The terms“substantially,” “essentially,” “approximately,” “about” or any otherversion thereof, are defined as being close to as understood by one ofordinary skill in the art, and in one non-limiting embodiment the termis defined to be within 10%, in another embodiment within 5%, in anotherembodiment within 1% and in another embodiment within 0.5%.

In the following description, numerous specific details are set forth.However, it is to be understood that embodiments of the disclosedtechnology may be practiced without these specific details. Referencesto “one embodiment,” “an embodiment,” “example embodiment,” “variousembodiments,” and other like terms indicate that the embodiments of thedisclosed technology so described may include a particular function,feature, structure, or characteristic, but not every embodimentnecessarily includes the particular function, feature, structure, orcharacteristic. Further, repeated use of the phrase “in one embodiment”does not necessarily refer to the same embodiment, although it may.

This disclosure presents a sensor having a front seal. For example, FIG.2 is a partial longitudinal cross-sectional view of one embodiment of asensor 200 having a front seal with various aspects set forth herein. InFIG. 2, the sensor 200 may be configured to include a header 201, asensing element 202, a housing 203, and an adapter 204. The header 201may be coupled to the housing 203. For example, the header 201 may besecured, bonded, welded, press fit or the like to the housing 203. Theheader 201 may be composed of glass, metal, ceramic material, or thelike. In one example, the header 201 may be composed of glass. Thehousing 203 may be composed of metal, ceramic material, or the like. Inone example, the housing 203 may be composed of metal. The header 201may be coupled to the sensing element 202. For example, the header 201may be secured, bonded, welded, press fit or the like to the sensingelement 202. The sensing element 202 may be capable of measuring anenvironmental condition such as pressure, temperature, humidity, or thelike. In one example, the sensing element 202 may be a piezoresistiveleadless sensor. In another example, the sensing element 202 may be apiezoresistive sensing network such as a Wheatstone bridge. The header201 may not enclose the sensing element 202. Instead, the header 201 maybe coupled to a back-side of the sensing element 202, leaving afront-side of the sensing element 202 protruding away from the header201 towards a front of the sensor 200.

In FIG. 2, the adaptor 204 may be coupled to the housing 203 so that afirst gap 207 may be disposed between the adaptor 204 and the sensingelement 202 and a second gap 208 may be disposed between the adaptor 204and the header 201. For example, the adaptor 204 may be secured, bonded,welded, press fit or the like to the housing 203. The adaptor 204 may becomposed of metal, ceramic material, or the like. In one example, theadaptor 204 may be composed of metal. The first gap 207 may keep theadaptor 204 from connecting or making contact with the sensing element202. Further, the first gap 207 may form a first cavity around the sidesof the sensing element 202. In one example, the first gap 207 may beless than 0.015 inches. In another example, the first gap 207 may be inthe range of 0.001 inches to 0.015 inches. Similarly, the second gap 208may keep the adaptor 204 from connecting or making contact with theheader 201. Further, the second gap 208 may form a second cavity aroundthe sides of the header 201. In one example, the second gap 208 may beless than 0.040 inches. In another example, the second gap 208 may be inthe range of 0.005 inches to 0.040 inches.

In this embodiment, the adaptor 204 may have a front surface 206, whichmay be used to form a front seal between the sensor 200 and a matingsurface such as an engine surface. Since the front seal may be ametal-to-metal seal, a stress may be generated in forming the frontseal. The first gap 207 and the second gap 208 may be used to reduce allor a portion of the stress that is transferred from the adaptor 204 tothe sensing element 202 or the header 201. Thus, the stress may betransferred through the adapter 204 to the housing 203 instead of beingtransferred through the adapter 204 to the header 201 or the sensingelement 202. In one example, the stress may be transferred through theadapter 204 to an outside of the housing 203 such as a screw housing anddown into a securing mechanism of the housing 203 such as threads of thescrew housing.

Furthermore, the first gap 207 may allow a fluid such as a gas or aliquid to be disposed between the adaptor 204 and the sensing element201, which may cause wear, corrosion, heat transfer or the like on thesensing element 201 or the adaptor 204. Similarly, the second gap 208may also allow a fluid to be disposed between the adaptor 204 and theheader 202, which may also cause wear, corrosion, heat transfer or thelike on the header 202, the adaptor 204 or the housing 203.

Any impact of a fluid on an adaptor, a header, a sensing element or ahousing may be reduced or eliminated. For example, FIG. 3 is a top viewof another embodiment of a sensor 300 having a front seal with variousaspects set forth herein. In FIG. 3, the sensor 300 may be configured toinclude a header (not shown), a sensing element 302, a housing 303 andan adapter 304. The adapter 304 may define an opening 309 of the sensor200. In one example, a shape of the opening 309 may be about square,circular, rectangular, oval, polygonal, or the like. The sensing element302 may be disposed within the opening 309. A first gap 307 may bedisposed between outer walls of the sensing element 302 and inner wallsof the adapter 304. Further, the first gap 307 may form a first cavityaround the sides of the sensing element 301. To reduce a volume of fluidthat may enter, exit, or be disposed in the first gap 307, a shape or asize of the opening 309 may be about equivalent to a shape or a size ofthe sensing element 302. In one example, the shape of the opening 309may be about equivalent to the shape of the sensing element 302. Inanother example, the size of the opening 309 may be about equivalent tothe size of the sensing element 302. In another example, the shape andthe size of the opening 309 may be about equivalent to the shape and thesize of the sensing element 302. The impact of a fluid disposed in thefirst gap 307 on the adapter 304, the header, the sensing element 302,or the housing 303 may be reduced or eliminated by limiting a volume ofthe fluid that may enter, exit, or be disposed in the first gap 307,which may also improve a flat frequency response of the sensing element302 since a smaller volume cavity around the sensing element 302 mayreduce, for instance, Helmholtz-related acoustic resonance.

This disclosure also presents a sensor having a front seal and aHelmholtz resonator. FIG. 4 is a partial longitudinal cross-sectionalview of another embodiment of a sensor 400 having a front seal and aHelmholtz resonator with various aspects set forth herein. In FIG. 4,the sensor 400 may be configured to include a header 401, a sensingelement 402, a housing 403, an adapter 404, and a screen 409. The header401 may be coupled to the housing 403. For example, the header 401 maybe secured, bonded, welded, press fit or the like to the housing 403.The header 401 may be composed of glass, metal, ceramic material, or thelike. In one example, the header 401 may be composed of a ceramicmaterial. The housing 403 may be composed of metal, ceramic material, orthe like. In one example, the housing 403 may be composed of ceramicmaterial. The header 401 may be coupled to the sensing element 402. Forexample, the header 401 may be secured, bonded, welded, press fit or thelike to the sensing element 402. The sensing element 402 may be capableof measuring an environmental condition such as pressure, temperature,humidity, or the like. In one example, the sensing element 402 may beused to measure a pressure and a temperature. The header 401 may notenclose the sensing element 402. Instead, the header 401 may be coupledto a back-side of the sensing element 402, leaving a front-side of thesensing element 402 protruding away from the header 401 towards a frontof the sensor 400.

In FIG. 4, the adaptor 404 may be coupled to the housing 403 so that afirst gap 407 may be disposed between the adaptor 404 and the sensingelement 402 and a second gap 408 may be disposed between the adaptor 404and the header 401. In one example, the adaptor 404 may be secured,bonded, welded, press fit or the like to the housing 403. The adaptor404 may be composed of metal, ceramic material, or the like. In oneexample, the adaptor 404 may be composed of a ceramic material. Thefirst gap 407 may keep the adaptor 404 from connecting or making contactwith the sensing element 402. Further, the first gap 407 may form afirst cavity around the sides of the sensing element 402. Similarly, thesecond gap 408 may keep the adaptor 404 from connecting or makingcontact with the header 401. Further, the second gap 408 may form asecond cavity around the sides of the header 401.

In this embodiment, the screen 411 may be disposed in front of thesensing element 401 defining a third cavity 409. The screen 411 may becomposed of metal, ceramic material, or the like. In one example, thescreen 411 may be composed of metal. In a typical sensor having a screendisposed in front of a sensing element defining a cavity, the screen incombination with the cavity forms a Helmholtz resonator that may slow aresponse time of the sensing element. However, the screen 409 incombination with the first cavity associated with the first gap 407, thesecond cavity associated with the second gap 408 and the third cavity409 may form a Helmholtz resonator that may not slow a response time ofthe sensing element 402. In one example, the response time of thesensing element 402 may be less than fifty microseconds (50 μsec.).

In another embodiment, a system may be configured to include a sensingelement; a header coupled to the sensing element; and a housing coupledto the header. Further, the system may be configured to include anadaptor coupled to the housing. A first gap may separate the adapter andthe sensing element. Also, a second gap may separate the adapter and theheader. A stress applied at a front surface of the adapter may betransferred to the housing. Further, the first gap may be used toisolate the sensing element from the stress. The second gap may be usedto isolate the header from the stress.

In another embodiment, the adaptor may not be connected to the sensingelement.

In another embodiment, the adaptor may not be in contact with thesensing element.

In another embodiment, the first gap may be less than 0.015 inches.

In another embodiment, the first gap may be in the range of 0.001 inchesto 0.015 inches.

In another embodiment, the adaptor may not be connected to the header.

In another embodiment, the header may not be in contact with theadaptor.

In another embodiment, the second gap may be less than 0.040 inches.

In another embodiment, the second gap may be in the range of 0.005inches to 0.040 inches.

In another embodiment, the sensing element may be a piezoresistiveleadless sensor.

In another embodiment, the sensing element may be used to measure anenvironmental condition.

In another embodiment, the environmental condition may be pressure.

In another embodiment, the adapter may be disposed around and may definean opening.

In another embodiment, the sensing element may be disposed in theopening.

In another embodiment, a shape of the opening may be about equivalent toa shape of the sensing element.

In another embodiment, the shape of the opening may be square.

In another embodiment, a size of the opening may be about equivalent toa size of the sensing element.

In another embodiment, the system may be further configured to include ascreen disposed in the opening of the adapter. A first cavity may bedisposed between the screen and the sensing element. Further, a secondcavity may be associated with the first gap. The screen in combinationwith the first cavity and the second cavity may form a Helmholtzresonator.

In another embodiment, the Helmholtz resonator may not reduce a responsetime of the sensing element.

In another embodiment, a third cavity may be associated with the secondgap.

In another embodiment, the screen in combination with the first cavity,the second cavity and the third cavity may form a Helmholtz resonator.

In another embodiment, a response time of the sensing element may beless than about fifty microseconds.

In another embodiment, the front surface of the adapter may be coupledto a mating surface.

In another embodiment, a system may be configured to include a sensingelement; a header coupled to the sensing element; a housing coupled tothe header; and an adaptor coupled to the housing. A screen may bedisposed in an opening of the housing. A first cavity may be disposedbetween the screen and the sensing element. Further, a second cavity maybe disposed between the adaptor and the sensing element. The screen incombination with the first cavity and the second cavity may form aHelmholtz resonator.

In another embodiment, a first gap between the adapter and the sensingelement may be less than 0.015 inches.

In another embodiment, a first gap between the adapter and the sensingelement may be in the range of 0.001 inches to 0.015 inches.

In another embodiment, the adaptor may not be connected to the header.

In another embodiment, a second gap between the adapter and the headermay be less than 0.040 inches.

In another embodiment, a second gap between the adapter and the headermay be in the range of 0.005 inches to 0.040 inches.

In another embodiment, the sensing element may be a piezoresistiveleadless sensor.

In another embodiment, the sensing element may be used to measure anenvironmental condition.

In another embodiment, the environmental condition may be pressure.

In another embodiment, the adapter may be disposed around and may definean opening.

In another embodiment, the sensing element may be disposed in theopening.

In another embodiment, a shape of the opening may be about equivalent toa shape of the sensing element.

In another embodiment, the shape of the opening may be square.

In another embodiment, a size of the opening may be about equivalent toa size of the sensing element.

In another embodiment, the Helmholtz resonator may not reduce a responsetime of the sensing element.

In another embodiment, a response time of the sensing element may beless than about fifty microseconds.

In another embodiment, the front surface of the adapter may be coupledto a mating surface.

In another embodiment, a stress applied at a front surface of theadapter may be transferred to the housing.

In another embodiment, the second cavity may isolate the sensing elementfrom a stress applied at a front surface of the adapter.

In another embodiment, a third cavity may be disposed between theadaptor and the header.

In another embodiment, the screen in combination with the first cavity,the second cavity and the third cavity may form a Helmholtz resonator.

In another embodiment, the third cavity may isolate the header from astress applied at a front surface of the adapter.

It is important to recognize that it is impractical to describe everyconceivable combination of components or methodologies for purposes ofdescribing the claimed subject matter. However, a person having ordinaryskill in the art will recognize that many further combinations andpermutations of the subject technology are possible. Accordingly, theclaimed subject matter is intended to cover all such alterations,modifications, and variations that are within the spirit and scope ofthe claimed subject matter.

Although the present disclosure describes specific examples,embodiments, and the like, various modifications and changes may be madewithout departing from the scope of the present disclosure as set forthin the claims below. For example, although the example methods, devicesand systems, described herein are in conjunction with a configurationfor the aforementioned sensor having a front seal and the aforementionedsensor having a Helmholtz resonator, the skilled artisan will readilyrecognize that the example methods, devices or systems may be used inother methods, devices or systems and may be configured to correspond tosuch other example methods, devices or systems as needed. Further, whileat least one example, embodiment, or the like has been presented in theforegoing detailed description, many variations exist. Accordingly, thespecification and figures are to be regarded in an illustrative ratherthan a restrictive sense, and all such modifications are intended to beincluded within the scope of the present disclosure. Any benefits,advantages, or solutions to problems that are described herein withregard to specific embodiments are not intended to be construed as acritical, required, or essential feature or element of any or all of theclaims. Any benefits, advantages, or solutions to problems that aredescribed herein with regard to specific examples, embodiments, or thelike are not intended to be construed as a critical, required, oressential feature or element of any or all of the claims.

What is claimed is:
 1. A system, comprising: a sensing element; a headercoupled to the sensing element; a housing coupled to the header; anadaptor coupled to the housing; and a screen disposed in an opening ofthe housing, wherein a first cavity is disposed between the screen andthe sensing element and a second cavity is disposed between the adaptorand the sensing element, and the screen in combination with the firstcavity and the second cavity form a Helmholtz resonator.
 2. The systemof claim 1, wherein a first gap between the adapter and the sensingelement is less than 0.015 inches.
 3. The system of claim 1, wherein afirst gap between the adapter and the sensing element is in the range of0.001 inches to 0.015 inches.
 4. The system of claim 1, wherein theadaptor is not connected to the header.
 5. The system of claim 1,wherein a second gap between the adapter and the header is less than0.040 inches.
 6. The system of claim 1, wherein a second gap between theadapter and the header is in the range of 0.005 inches to 0.040 inches.7. The system of claim 1, wherein the sensing element is apiezoresistive leadless sensor.
 8. The system of claim 1, wherein thesensing element is used to measure an environmental condition.
 9. Thesystem of claim 8, wherein the environmental condition is pressure. 10.The system of claim 1, wherein the adapter is disposed around anddefines an opening and the sensing element is disposed in the opening.11. The system of claim 10, wherein a shape of the opening is aboutequivalent to a shape of the sensing element.
 12. The system of claim11, wherein the shape of the opening is square.
 13. The system of claim11, wherein a size of the opening is about equivalent to a size of thesensing element.
 14. The system of claim 1, wherein the Helmholtzresonator does not reduce a response time of the sensing element. 15.The system of claim 1, wherein a response time of the sensing element isless than about fifty microseconds.
 16. The system of claim 1, whereinthe front surface of the adapter is coupled to a mating surface.
 17. Thesystem of claim 1, wherein a stress applied at a front surface of theadapter is transferred to the housing.
 18. The system of claim 1,wherein the second cavity isolates the sensing element from a stressapplied at a front surface of the adapter.
 19. The system of claim 1,wherein a third cavity is disposed between the adaptor and the header.20. The system of claim 19, wherein the screen in combination with thefirst cavity, the second cavity and the third cavity form a Helmholtzresonator.
 21. The system of claim 19, wherein the third cavity isolatesthe header from a stress applied at a front surface of the adapter.